The Research About Synthesis And Luminescence Properties Of Rare Earth Doped Silicate Glass-Glass Ceramics And NaYF₄ Nanocrystals

Rare earth ion-doped luminescent materials have attracted extensive attention due to their advantages of excellent optical performance and structural stability.Through the B2O3-SrO-SiO2/BaF2-SiO2 system glass and glass ceramics doped in the Er/Yb/Eu/Dy/Tb synthesized by sol-gel method and NaYF4 nanocrystals doped in the Er/Yb prepared by hydrothermal method,the effects of heat treatment temperature and atmosphere of glass and glass ceramics,as well as the type and concentration of doped ions on structure and luminescence properties were systematically studied in the thesis.The effect of the conditions of synthesis and the concentration of the package on Structure or morphology and its luminous properties of chloride nanocrystals prepared by hydrothermal method was studied in the thesis.The specific research content and results are as follows:(1)In the synthesized Er/Yb single-doped and co-doped 5B2O3-5SrO-90SiO2 system glass and glass ceramics,the effects of heat treatment temperature and the concentration of doped ions on the luminescent properties of the samples were studied.The results of the research show that with the increase of the heat treatment temperature,the glassy matrix will gradually transform into a transparent glass ceramic which contains nanocrystals.Stimulated by 980 nm,the sample after 900? heat treatment has the highest emission intensity when the rare earth ion concentration is 0.02Yb-0.01Er,and there is transmission of energy of Yb?Er.The process of emission of Er ions in the sample is a two-photon process was found with transformation of fire mechanism.(2)The effect of the atmosphere during heat treatment and the rare earth ion doping/co-doping on the luminescence performance of the sample was investigated by 5BaF2-95SiO2system glass ceramics doped in Eu/Dy/Tb prepared by the sol-gel method.The results show that the 5D0?7Fj transition emission of Eu3+,the 5D4?7F5 magnetic dipole transition e1ission of Tb3+ at 548 nm,and the Dy3+ at 580nm which comes from 4F9/2?6H13/2 charge transition,the characteristic emission of Eu2+ at 440 nm corresponds to the 4f65d1-4f7 transition were appeared.With the increase of Dy,emission intensities of Tb and Eu in the sample were increased when they are co-doped.However,the Eu will affect the emission intensity of Tb,and there is Dy3+?Eu3+transmission of energy.(3)First,the Er/Yb co-doped NaYF4 nanocrystals were prepared by hydrothermal method,and then the phosphor was coated and shaped by using polymethyl methacrylate.The effects of different surfactants on the structure of NaYF4 crystals in the process of hydrothermal synthesis were mainly discussed,and the effect of the concentration of polymethyl methacrylate-coated phosphor on the luminescent properties was studied.As a result,when sodium dodecylbenzene sulfonate was used as a surfactant,the shape and crystal phase uniformity of the sample are relatively good;besides,when the concentration of the coated phosphor is 0.1%,the emission intensity of the sample under the excitation of 980 nm is not only optimum,but the infrared-visible transmittance of the sample is also more than 93%at this time.t the same time,the above conversion emission process is a two-photon process has been found.